Question

A particle starts from rest moves 20m in 2 seconds next 160m in4 seconds. Calculate the acceleration after the 7 seconds.

Answer 1

Answer:

Acceleration after 7 seonds is 10 m/s^2

Explanation:

Initial velocity u=0

Distance traveled S= 20 m

time taken  t= 2sec

Now we can find the acceleration for this using equation of motion.

$S=ut+\frac{1}{2} at^2\\20=0\times t+\frac{1}{2}\times a\times2^2\\a=\frac{40}{4} \\a=10 m/s^2$

Velocity at the end of 2 sec is

$v=u+at\\v=0+10\times 2\\v=20 m/s$

Similarly at the after 4 sec, we have distance S=160 m, t=4 sec

Acceleration is of this period is

$S=ut+\frac{1}{2} at^2\\160=20\times 4+\frac{1}{2}\times a\times4^2\\a=\frac{160}{16} \\a=10 m/s^2$

From we can observe that the acceleration is constant. Acceleration after 7 seonds is 10 m/s^2